This invention is generally directed to processes for the preparation of anilides, and more specifically anilide couplers which can be selected for the preparation of photogenerating azo compositions, such as bisazos and trisazos. In one embodiment of the present invention, there are provided simple, economical processes for the preparation of photoreceptor grade anilide couplers, such as 2-hydroxy-11H-benzo(a)carbozole-3-carboxanilide and its derivatives, by the reaction of an aromatic, especially phenyl ester obtained from an acid with an aniline. One process embodiment of the present invention comprises the reaction of a hydroxybenzocarbazole carboxylic acid with phenol, followed by the reaction of the resulting carboxylate with an aniline. The couplers resulting with the processes of the present invention can be selected for the preparation of azo photogenerating pigments, reference for example U.S. Pat. No. 4,916,039, and 4,925,758, the disclosures of which are totally incorporated herein by reference. The aforementioned photogenerating pigments can be selected for layered photoresponsive imaging members comprised of a charge transport layer, a photogenerating layer and a supporting substrate. More specifically, the azo photogenerating pigments that can be obtained with the processes of the present invention can be selected for layered photoconductive imaging members with improved xerographic properties, inclusive of high charge acceptance, low dark decay, high photosensitivity, including photosensitivity in the wavelength regions of from about 400 to about 850 nanometers, enabling their selection for electrophotographic, especially xerographic imaging systems, LED printers, and diode laser printers which are usually sensitive to wavelengths of from about 660 to about 800 nanometers. The imaging members can be comprised of photoconductive layers comprised of the bisazo pigments and charge or hole transport layers, especially those comprised of aryl amines, which members can be sensitive to light in the wavelength region of from about 400 to about 800 nanometers. The resulting members are responsive to visible light, and near infrared illumination originating from laser printing apparatuses wherein, for example, gallium arsenide diode lasers are selected. The photoresponsive imaging members can also, for example, contain situated between a photogenerating layer and a hole transporting layer, or situated between a photogenerating layer and a supporting substrate with a charge transport layer in contact with the photogenerating layer, a photoconductive composition comprised of the photogenerating azo pigments.
Examples of advantages associated with the processes of the present invention include obtaining couplers with high purity, for example from about 95 to about 99 percent or higher in embodiments; immediate utilization of the couplers obtained for the preparation of bisazo photogenerating pigments; acceptable yields of, for example, from about 55 to about 95 percent; the product can be easily purified by conventional techniques such as solvent extraction, recrystallization and the like; scale up to manufacturing conditions is enabled in embodiments thereof; the products obtained can be, after synthesis, selected for the preparation of photogenerating azo pigments, and wherein the resulting xerographic properties of the photoconductive members such as dark decay, charge acceptance, and charge stability are acceptable; and the like.
The preparation by certain methods of anilide couplers are known. More specifically, there is disclosed in Japanese Laid Open 59-137459, 1984, the preparation of 2-hydroxy-11H-benzo(a)carbazole-3-carbohydrozide by initially preparing a methyl ester (methyl 2-hydroxy-11H-benzo(a)carbazole-3-carboxylate) and condensing this ester with a hydrazine. Also, in the Color Index, Third Edition, Volume 4, published by the Society of Dyes and Colorants, there is illustrated the preparation of methoxy anilides, such as 2-hydroxy-11H-benzo(a)carbazole-3-carbox-2'-methyl-4'-methoxyanilide, by the condensation of an acid with an appropriate aniline. Other representative prior art disclosing the preparation of couplers include U.S. Pat. Nos. 4,916,039 and 4,925,758 wherein there is illustrated the conversion of an appropriate acid to an acid halide such as acid chloride, and subsequently reacting the resulting acid halide with an aniline to obtain an anilide coupler.
Also, many processes are known for the preparation of azo photogenerating pigments, such as azotization and coupling, reference U.S. Pat. No. 3,898,084. Examples of aromatic amines selected for the preparation of azo pigments include 2,7-diaminofluorenone, reference for example, U.S. Pat. Nos. 4,797,337; 4,830,942; 4,822,705; 4,596,754; 4,618,672; 4,481,271; 4,400,455; 4,390,608; 4,327,176; 4,314,015; 4,299,015; 4,299,896 and 4,551,404 possess in many instances high sensitivity and high electrical stability. Azo pigments synthesized from anilide couplers of 2-hydroxy-11H-benzo(a)carbazole-3-carboxylic acid enable imaging members with photoresponses at longer wavelengths, for example beyond 700 nanometers.
In U.S. Pat. No. 4,916,039 there are disclosed photoconductors with charge generating pigments comprised of certain azo compounds, reference the formula illustrated in the Abstract of the Disclosure, and in column 3. The aforementioned azo pigments are prepared by the coupling reaction of 2-hydroxy-3-carbamoylbenzo-alpha-carbazole derivatives of Formula VI with diazonium salts, reference columns 6 and 7. The coupling reaction is accomplished by dissolving the diazonium salts and a coupler, such as those obtained with the processes of the present invention in an organic solvent, such as DMF and DMSO and adding dropwise thereto an alkaline aqueous solution at a temperature of from about -10.degree. to about 40.degree. C., see column 7 for example. A similar teaching is present in U.S. Pat. No. 4,925,758.
Imaging members with certain bisazo pigments are known, reference for example U.S. Pat. No. 3,898,084, which discloses, for example, the azo pigment chlorodiane blue in a photoconductive imaging member. The aforementioned chlorodiane blue can be prepared by azotizing dichlorobenzidine in HCl, for example 18 percent HCl, by the addition of a sodium nitrite, followed by the addition of HBF.sub.4, enabling the formation of the tetrazonium salt. This salt can then be coupled with 2-hydroxy-3-naphthanilide to permit the formation of the chlorodiane blue pigment, which formation is accomplished in the presence of sodium acetate.
U.S. Pat. No. 3,574,181 discloses disazo compounds useful as coloring agents. Composite electrophotographic photosensitive materials containing various azo compounds are disclosed in U.S. Pat. No. 4,618,672, wherein bisazo compounds particularly suitable for use in the charge generating layer of a layered electrophotographic photoconductor are illustrated. Similarly, an article by M. Hashimoto entitled "Electrophotographic Sensitivity of Fluorenone Bisazo Pigments", Electrophotography, Vol. 25, No. 3 (1986), discloses disazo compounds as charge generating materials in electrophotographic layered photoreceptors. Further, Japanese Patent Kokai No. 54-20736 discloses disazo pigments as constituents in electrophotographic processes. Japanese Patent 58-177955 also discloses many disazo compounds suitable for use in the photosensitive layer of an electrophotographic device.
U.S. Pat. No. 4,713,307, the disclosure of which is hereby totally incorporated by reference, discloses photoconductive imaging members containing a supporting substrate, certain azo pigments as photogenerating materials, and a hole transport layer that preferably contains an aryl diamine compound dispersed in an inactive resinous binder. The aforementioned azo pigments can be obtained from the couplers generated with the processes of the present invention.
U.S. Pat. No. 4,797,337, the disclosure of which is totally incorporated herein by reference, discloses a photoconductive imaging member comprising a supporting substrate, a hole transport layer, and a photogenerating layer comprising specific disazo compounds, which disazo compounds are prepared as illustrated herein, that is by the azotization and coupling reactions illustrated in the aforementioned prior art.
Additional references illustrating layered organic electrophotographic photoconductor elements with azo, bisazo, related compounds, and processes thereof include U.S. Pat. No. 4,390,611, U.S. Pat. No. 4,551,404, U.S. Pat. No. 4,596,754, Japanese Patent 60-64354, U.S. Pat. No. 4,400,455, U.S. Pat. No. 4,390,608, U.S. Pat. No. 4,327,168, U.S. Pat. No. 4,299,896, U.S. Pat. No. 4,314,015, U.S. Pat. No. 4,486,522, U.S. Pat. No. 4,486,519, U.S. Pat. No. 4,555,667, U.S. Pat. No. 4,440,845, U.S. Pat. No. 4,486,800, U.S. Pat. No. 4,309,611, U.S. Pat. No. 4,418,133, U.S. Pat. No. 4,293,628, U.S. Pat. No. 4,427,753, U.S. Pat. No. 4,495,264, U.S. Pat. No. 4,359,513, U.S. Pat. No. 3,898,084, U.S. Pat. No. 4,830,944, U.S. Pat. No. 4,820,602, and Japanese Patent Publication 60-111247.
In U.S. Pat. No. 4,833,052, the disclosure of which is totally incorporated herein by reference, there are illustrated certain bisazo photoconductive imaging members. Examples of bisazo compounds disclosed in this patent include those of the formulas as illustrated in column 4, such as 4,4'-bis(1"-azo-2"-hydroxy-3"-naphthanilide)-1,1'-dianthraquinonylamine.
In a patentability search report the following United States patents were recited: U.S. Pat. No. 4,830,943 relating to a photoconductor with a disazo having couplers, such as anilides, carbozole, and the like; U.S. Pat. No. 4,833,052 which discloses a photoconductive imaging member comprising a disazo compound with an azoic coupler, such as an anilide and the like, note column 7, lines 44 to 58; U.S. Pat. No. 4,868,880 which discloses a photosensitive layer comprising an azo pigment having an organic residue, see column 2, lines 53 to 65; and U.S. Pat. No. 4,830,944 which discloses a charge generation material comprising a disazo pigment with couplers, such as those derived from carboxylic acids.